Video QA | Glossary

Ad verification tags are third-party tags used to monitor parameters like viewability. Depending on setup they can also block an ad from displaying based on parameters like page content keywords.

LUFS (loudness units relative to full scale) is the overall level of the audio track. It's important to have a strictly defined overall loudness level to ensure good-sounding audio and to avoid annoying dynamic bumps between commercials and programme audio. The average audio test measures the LKFS/LUFS value of the audio track and compares this to a pre-determined reference level while allowing for a certain deviation.

A codec processes video or audio and stores it in a stream of bytes. Codecs use algorithms to effectively shrink the size of the audio or video file, and then decompress it when needed.

Sample rate is the average number of samples of audio per second. It is expressed in Hz or kHz.

The true peak level is the absolute peak of an audio waveform as it will be heard once the digital audio has been converted to an analogue signal that can be played through speakers.

The bitrate is the number of bits that are processed in a unit of time. In general, a higher bitrate will accommodate higher quality. However, the higher the bit rate, the more bandwidth is required to play back the video.

The chroma subsampling check validates the encoding of luma/chroma sampling. 4:2:0 is by wide margin the most common setting in online video.

Only calls to domains approved by your account are allowed. Ads with calls to unapproved domains are not allowed. If you have any questions or think a domain should be approved reach out to your contact person.

A container usually bundles the audio and video data in one organised package. In addition, the container can contain metadata, subtitles, and additional audio files such as different spoken languages.

Dimensions are the size/ratio of the video and can be expressed either as a pixel resolution or as a relative aspect ratio.

The duration is the length in seconds of the video.

The file size is the size of the file in kilobytes. Resolution, duration, bitrate, frame rate and compression are some of the properties that will affect quality and file size.

The frame rate is the rate at which consecutive images (frames) appear on a display. It is expressed in fps (frames per second).

Letter- or pillarboxing occurs when a clip is displayed in a different aspect ratio context than it was produced for. The most common case is displaying 16:9 content in 4:3 context (letterboxing) or the reverse (pillarboxing).

HTTPS protects the privacy and security of users. All network requests must be made over HTTPS.

The VAST XML can include multiple media files. Required media files are media files with specific properties (format, bitrate and/or resolution) that must be declared in the VAST XML in order for the VAST tag to be accepted.

Video is displayed using either the interlaced or the progressive scanning method.

Detect two types of telecine/pulldown artefacts; duplicate frames and interlaced frames. Note that these tests are indicative and not conclusive, please review the video visually checking for judder or combing artefacts.

Timecode is an extra data stream added to video files to help alleviate real-time/frame count time drift that would otherwise cause issues in some broadcasting environments.

VAST API framework

VAST creative count

VAST version

VAST XML syntax

Video codec